This study investigates the bending-bearing capacity and design method of Transformed Triangular Corrugated Steel Plates (TT-CSPs) with top stringers adopted in trestles subjected to possible pure bending. Elastic buckling load and ultimate strength are derived through theoretical deduction and numerical analysis. Exploration focuses on the impact of boundary conditions, aspect ratio, corrugation density, and top stringers on buckling behavior and ultimate strength. This paper advances a design approach for the bending-bearing capacity of TT-CSPs with top stringers. Findings indicate that the vertical boundaries of TT-CSPs cannot meet the plane assumption and are close to being free-warping. Higher corrugation densities increase structural stiffness and uniformity, while TT-CSP height variations significantly affect stability. Top stringers behave as lateral constraints and undergo significant bending stresses, with their various buckling modes influencing the bending-bearing stability capacity of TT-CSPs.